Spade-type drill bits, hereinafter referred to as "spade bits", are known in the art for drilling or boring holes through wood and other materials. Typically, the spade bit includes an elongated shank with a spade bit portion at one end of the shank for boring through the wood or other material. The opposite end of the shank is received and held by the drill during the drilling operation.
The spade bit portion of the spade bit generally includes a plate-like structure, sometimes planar, which is generally thinner than the shank. Sharpened cutting edges are provided that engage and cut the wood or other material during drilling. The spade bit portion also typically includes a centering tip.
Spade bits come in a variety of sizes for drilling holes anywhere from 1/4 inches in diameter or smaller to 1 and 1/2 inches in diameter or larger. Spade bits are useful in drilling holes of different sizes and are used instead of conventional auger drill bits or twist drill bits. Prior problems with known spade bits are that they have a tendency to become dull quickly, do not cut well through desired materials even when sharp, and are difficult to manufacture and sharpen.
Several significant concerns exist both for drill bits generally, and also in particular, for spade bits. One significant concern is the performance characteristics of the spade bit. Considerations such as the speed of cutting holes and the ease of cutting holes are important. In some circumstances, the length of time for the spade bit to cut through the material is important. These considerations are also related to the power and torque requirements necessary to cut the hole. Power and torque requirements may impact whether the spade bit can be used with ordinary electric drills or conventional cordless drills.
Another consideration related to performance is the ability of the spade bit to be easily resharpened after the spade bit has been used for a period of time and becomes dull. Complex shapes for the cutting edges and surfaces may make it difficult or impossible for the spade bit to be sharpened without special equipment. Complex shapes may also make it too time consuming to resharpen, meaning that the blades would have to be disposed of once they became dull. The ability to produce even, smoothly cut holes is also desireable in a spade bit.
A further consideration with respect to the spade bits relates to the ability to manufacture the spade bits easily and inexpensively. Complex shapes or complex processes may excessively raise the costs to manufacture the bits.
There has existed a long and unfilled need in the prior art for a spade bit and method for manufacturing the same which addresses the above and other problems and concerns relating to spade bits.